package gitea

import (
	"context"
	"encoding/json"
	"fmt"
	"net/url"
)

type PullRequest struct {
	Number  int    `json:"number"`
	Title   string `json:"title"`
	Body    string `json:"body"`
	HTMLURL string `json:"html_url"`
	State   string `json:"state"`
	Draft   bool   `json:"draft"`
	Head    struct {
		Ref string `json:"ref"`
	} `json:"head"`
	Base struct {
		Ref string `json:"ref"`
	} `json:"base"`
}

type CreatePullRequestArgs struct {
	Title string `json:"title"`
	Body  string `json:"body"`
	Head  string `json:"head"`
	Base  string `json:"base"`
	Draft bool   `json:"draft"`
}

func (c *Client) CreatePullRequest(ctx context.Context, owner, repo string, args CreatePullRequestArgs) (*PullRequest, error) {
	p := fmt.Sprintf("/api/v1/repos/%s/%s/pulls", owner, repo)
	payload, err := json.Marshal(args)
	if err != nil {
		return nil, err
	}
	body, status, err := c.PostJSON(ctx, p, payload)
	if err != nil {
		return nil, err
	}
	if err := MapStatus(status, body); err != nil {
		return nil, err
	}
	var pr PullRequest
	if err := json.Unmarshal(body, &pr); err != nil {
		return nil, err
	}
	return &pr, nil
}

func (c *Client) GetPullRequest(ctx context.Context, owner, repo string, index int) (*PullRequest, error) {
	p := fmt.Sprintf("/api/v1/repos/%s/%s/pulls/%d", owner, repo, index)
	body, status, err := c.GetJSON(ctx, p)
	if err != nil {
		return nil, err
	}
	if err := MapStatus(status, body); err != nil {
		return nil, err
	}
	var pr PullRequest
	if err := json.Unmarshal(body, &pr); err != nil {
		return nil, err
	}
	return &pr, nil
}

type PullRequestFile struct {
	Filename  string `json:"filename"`
	Status    string `json:"status"` // added | modified | deleted | renamed
	Additions int    `json:"additions"`
	Deletions int    `json:"deletions"`
}

func (c *Client) GetPullRequestFiles(ctx context.Context, owner, repo string, index int) ([]PullRequestFile, error) {
	p := fmt.Sprintf("/api/v1/repos/%s/%s/pulls/%d/files", owner, repo, index)
	body, status, err := c.GetJSON(ctx, p)
	if err != nil {
		return nil, err
	}
	if err := MapStatus(status, body); err != nil {
		return nil, err
	}
	var files []PullRequestFile
	if err := json.Unmarshal(body, &files); err != nil {
		return nil, err
	}
	return files, nil
}

// GetPullRequestDiff returns the raw unified diff. The endpoint serves text/plain, not JSON,
// so we use doRaw to bypass the json Accept header expectation.
func (c *Client) GetPullRequestDiff(ctx context.Context, owner, repo string, index int) ([]byte, error) {
	p := fmt.Sprintf("/api/v1/repos/%s/%s/pulls/%d.diff", owner, repo, index)
	resp, err := c.doRaw(ctx, "GET", p, nil)
	if err != nil {
		return nil, err
	}
	if err := MapStatus(resp.Status, resp.Body); err != nil {
		return nil, err
	}
	return resp.Body, nil
}

func (c *Client) ListPullRequests(ctx context.Context, owner, repo, state, head string, page, limit int) ([]PullRequest, error) {
	if page < 1 {
		page = 1
	}
	if limit < 1 {
		limit = 30
	}
	p := fmt.Sprintf("/api/v1/repos/%s/%s/pulls?state=%s&page=%d&limit=%d",
		owner, repo, url.QueryEscape(state), page, limit)
	if head != "" {
		p += "&head=" + url.QueryEscape(head)
	}
	body, status, err := c.GetJSON(ctx, p)
	if err != nil {
		return nil, err
	}
	if err := MapStatus(status, body); err != nil {
		return nil, err
	}
	var prs []PullRequest
	if err := json.Unmarshal(body, &prs); err != nil {
		return nil, err
	}
	return prs, nil
}